JPH0493340A - Olefin polymer composition - Google Patents

Abstract

PURPOSE:To obtain the title compsn. excellent in antistatic properties and rigidity by compounding an olefin polymer or an olefin-unsatd. ester copolymer with a specific ethylenic potassium ionomer in a specified ratio. CONSTITUTION:76-90wt.% olefin polymer or olefin-unsatd. ester copolymer (e.g. a PE) is compounded with 10-24wt.% ethylenic potassium ionomer contg. potassium ions in a concn. of 1.5mol/g-resin or higher (e.g. an ionomer obtd. by neutralizing a specified amt. of methacrylic acid in an ethylene-methacrylic acid copolymer with potassium ions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to novel olefin polymer compositions. More specifically, the present invention relates to an olefin polymer composition with improved non-static properties and rigidity.

[Prior art] Olefin polymers (including copolymers of olefins) such as high-density polyethylene, low-density polyethylene, and polypropylene, and olefins such as ethylene/vinyl acetate copolymers and ethylene/ethyl acrylate copolymers. Copolymers of unsaturated esters are molded and utilized by various molding methods such as extrusion molding, injection molding, blow molding, and vacuum molding. These polymers are required to have antistatic or antifogging properties in many applications, and various antistatic agents are added to these polymers for this purpose, but it is difficult to maintain their effectiveness for a long period of time. It's difficult. Although it is possible to increase the sustainability of the effect by blending a large amount of antistatic agent, it is not a generally applicable method because it causes undesirable phenomena such as flaking and whitening on the surface of the molded product, which impairs the product value. There wasn't.

On the other hand, there are cases where further improvement in rigidity is required for these olefin polymers and copolymers of olefin and unsaturated esters, but there are many ways to improve rigidity without substantially impairing the original properties. It is accompanied by difficulties.

[Problems to be Solved by the Invention] Recognizing the technical issues described above, the present inventors have investigated the modification of olefin polymers and copolymers, such as improving antistatic properties and rigidity. . As a result, we have found a method to improve the charging properties and rigidity while maintaining the excellent properties of olefin polymers and copolymers.

Therefore, an object of the present invention is to provide an olefin polymer or copolymer composition that can be used in various molded products and has improved antistatic properties and rigidity.

[Means for Solving the Problems] According to the present invention, 76 to 90% by weight of an olefin polymer or a copolymer of an olefin and an unsaturated ester, and ethylene having a potassium ion concentration of 1.5 mmol/g resin or more. An olefin polymer composition comprising 10-24% by weight of potassium ionomer is provided.

In the present invention, the olefin polymer is a general term for olefin homopolymers and copolymers of two or more olefins, and these may be of high crystallinity, low crystallinity, or non-quality. There may be. Examples of olefins include ethylene, propylene, l-butene, l-pentene, 1-hexene, 1-octene, l-decene, 4
Examples include -methyl-1-pentene, butadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene. More specifically, olefin polymers include high-, medium-, or low-density polyethylene, linear low-density polyethylene, and low-crystalline or non-grade ethylene.
Examples include an a-olefin copolymer or an ethylene/a-olefin diene copolymer, polypropylene, poly-1-butene, and poly-4-methyl-1-pentene.

Examples of the unsaturated ester component in the copolymer of olefin and unsaturated ester of the present invention include vinyl esters such as vinyl acetate and vinyl propionate, esters of unsaturated acids such as acrylic acid, methacrylic acid, and maleic acid;
For example, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, te acrylate
rt-butyl, isooctyl acrylate, acrylic acid 2
Examples include -ethylhexyl and methyl methacrylate. The proportion of the unsaturated ester component in the copolymer is, for example, 1 to 60% by weight, preferably 5 to 5% by weight.
0% by weight can be used. More specific examples of copolymers include ethylene/vinyl acetate copolymer, ethylene/methyl acrylate copolymer, ethylene/methyl methacrylate copolymer, ethylene/ethyl acrylate copolymer, and ethylene/acrylic copolymer. Examples include n-butyl acid copolymer and ethylene/isobutyl acrylate copolymer.

Melt flow rate of olefin polymer or copolymer of olefin and unsaturated ester (hereinafter referred to as MFR)
varies depending on the purpose of molding, but for example, for ethylene-based polymers or copolymers, 190°C, 2160°C
MFR at g load is 0, 05-1000 g/
10 minutes, and < +, :o, 1 to 100 g/l (1 minute is preferred.

Olefin polymers or copolymers of olefins and unsaturated esters may be used alone or in combination of two or more. It may also be cross-linked.

In the present invention, an ethylene ionomer having a potassium ion concentration of 1.5 mmol/g FQ fat or more, preferably 17 mmol/g resin or more is added to such an olefin polymer or a copolymer of olefin and unsaturated ester. It is blended. Even when an ethylene ionomer with a potassium ion concentration of less than 1.5 mmol/g FH fat is blended, no significant improvement in antistatic properties is observed.

An ethylene ionomer with such a potassium ion concentration can be obtained by ionizing the unsaturated carboxylic acid site of an ethylene/unsaturated carboxylic acid copolymer or an ethylene/unsaturated carboxylic acid/unsaturated carboxylic acid ester copolymer;
It can be produced by a method such as saponifying an ethylene/unsaturated carboxylic acid ester copolymer.

The composition of each copolymer component of the ethylene ionomer is 40 to 84% by weight of ethylene units, particularly 70 to 82% by weight.
, unsaturated carboxylic acid and its potassium salt units are 16-3
5% by weight, especially 18-30% by weight, 0-40% by weight, especially 0-30% by weight of unsaturated carboxylic acid ester units
Preferably, it falls within this range. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, and monoethyl maleate. Further, as the unsaturated carboxylic acid ester, for example, those exemplified above can be cited as representative examples.

The blending ratio of the olefin polymer or the copolymer of olefin and unsaturated ester and the ethylene potassium ionomer is 76-90% by weight, preferably 76-85% by weight, and 10-24% by weight, preferably 15-24% by weight of the latter. 2
It is 4% by weight. If the ionomer component is less than the above range, the antistatic effect and the stiffness improvement effect will be small. Furthermore, if the ionomer component exceeds the above range, the inherent properties of the olefin polymer or copolymer of olefin and unsaturated ester will be impaired, and effects such as foaming due to increased water absorption and poor compatibility will appear. It tends to have disadvantages such as opacity and low tear strength.

Various additives can be added to the olefin polymer composition of the present invention depending on the purpose of use. Examples of such additives include antioxidants, light stabilizers, ultraviolet absorbers, nucleating agents, pigments, dyes, antifog agents, heat insulating agents, lubricants, inorganic fillers, blowing agents, crosslinking agents, etc. I can do it.

The olefin polymer composition of the present invention can be prepared by melt mixing using a melt mixing device such as an extruder.

The composition may be molded immediately after melt-mixing, or it may be pelletized after melt-mixing and then molded using a separate melt-forming machine. Ethylene-based potassium ionomers tend to absorb moisture during storage, and in order to prevent foaming in molded products, it is necessary to mold them using a vented extruder or to mold the olefin polymer composition once into pellets. It is better to adopt methods such as

fruit! ff1lt Ethylene-based potassium ionomer in which 71% of the methacrylic acid in the ethylene/methacrylic acid copolymer (methacrylic acid content 7.5 mol%) is neutralized with potassium ions (potassium ion concentration 1.65 mmol/g resin) , M.F.
RO, I g/10 min) 15 parts by weight and low density polyethylene (density 0.924 g/cm3MF R1,5 g/
(10 minutes) A blown film with a thickness of 100 ul was formed from 85 parts by weight.

After 3 days of molding, the film was manufactured by Tokyo Denshi ■, high resistance mode.
l When the surface resistivity was measured with TB-3, it was 1012
It was Ω. Also, if you rub the film strongly with a cotton cloth, there will be no
．． The 50 m square tissue paper did not stick and was not charged.

In Example 1, the amount of ethylene potassium ionomer used was 23 parts by weight, and the amount of low density polyethylene was 7 parts by weight.
A blown film was formed from a composition of ethylene potassium ionomer and low density polyethylene in the same manner as in Example 1 except that the amount was changed to 7 parts by weight, and tested in the same manner as in Example 1. The obtained blown film exhibited non-static properties as in Example 1.

A blown film made from the low-density polyethylene husk used in Example 1 was subjected to the same test, and the surface resistivity was 1016Ω, and it was easily charged by friction with cotton cloth.

Compare! 1 In Example 2, the amount of ethylene potassium ionomer used was 30 parts by weight, and the amount of low density polyethylene used was 7 parts by weight.
A blown film was molded in the same manner as in Example 1 except that the amount was changed to 0 parts by weight, but foaming was observed in the blown film.

Example 1: Ethylene-based potassium ionomer 2 used in Example 1
A press sheet with a thickness of 2 ml and 1 m was prepared from 0 parts by weight and 80 parts by weight of ethylene/vinyl acetate copolymer (vinyl acetate content 12% by weight, MFR 9 g/10 minutes). Molding 3
The surface resistivity after several days was 10+2Ω, and there was no triboelectric charging property. Also, the bending rigidity (JIS 7106) is 7
It was 5 MPa.

Comparison (1) For comparison, a press sheet containing only the ethylene/vinyl acetate copolymer used in Example 3 was prepared in the same manner as in Example 3. When the same test as in Example 3 was conducted, the surface resistivity was 10'5 Ω, indicating triboelectric charging properties. Moreover, its bending rigidity was 67 MPa.

[Effects of the Invention] According to the present invention, an olefin polymer composition having excellent non-static properties and rigidity can be obtained. Utilizing these properties, the polymer composition of the present invention can be used in films, vibrators, tubes,
It can be used for molded products of various shapes such as hollow containers and injection molded products.

Claims (1)

[Claims] (1) An olefin polymer consisting of 76-90% by weight of an olefin polymer or copolymer of olefin and unsaturated ester and 10-24% by weight of an ethylene potassium ionomer with a potassium ion concentration of 1.5 mmol/g resin or more. Coalescing composition.